Watching "Amnesia Curiosa" inspires an off-kilter state of mind. The performance group rainpan 43 creates a droll, deadpan scientific mood that makes the audience happy to be served banana slices on toothpicks while making believe they're tasting brains.

Or tasting souls, more accurately, or whatever untouchable bit of humanity stores memory and thought. The fleeting nature of consciousness -- remembering, and even existing -- is the wispy subject of this engaging, oddball entertainment, the second of three shows in the rainpan 43 festival this month at the Studio Theatre.

"It really is amazing to be anything at all," one of the two performers says in the early going, which features a physical exam that's almost worthy of the Marx Brothers.

You might call "Amnesia Curiosa" a comedy if it were more traditionally structured. As it is, Trey Lyford and Geoff Sobelle, who devised the piece with director Andrew Dawson, are performing more of an intellectual sideshow. It begins with the audience touring through a small museum backstage at the Studio's Mead Theatre, with artifacts displayed on tables and in cases. The first object you see: string -- as in the thing you tie around your finger to help you remember.

That's typical of "Amnesia's" puckish understatement, although Lyford and Sobelle aren't above pure silliness. Examples: the "shh-shh" sounds they make when opening make-believe sliding doors, and the absurd fun they have with fake mustaches.

But as they move back and forth between being examiners and the examined, they also lay claim to poignancy, with mortality as a sober motif. This theme is often literally in Sobelle's hands: He economically evokes a dying bird and a misremembering grandmother with the neatest of gestures. The grandmother, in particular, appears like a trick up his sleeve.

The slight trouble with "Amnesia" is that it not only riffs whimsically on its themes, it also meanders occasionally, and sometimes stops dead in its tracks. There is space in the 80-minute piece for your own mind to wander to the news of the day or the grocery list, then back to the eccentrically stitched-together show.

Luckily, Lyford and Sobelle share an attractively low-key style. One-liners are served very dry, and they keep the mood loose and relaxed as they do their pseudo-scientific thing. The atmosphere is faux 19th century, never losing the museum/surgical theater vibe it establishes early, even when the dialogue and gizmos (a tape recorder, most notably) are more patently modern.

And despite its old-fashioned trappings, it is ultramodern -- ironic, disciplined and unbound by the usual dramatic conventions. In one typical slapstick/mystical bit, Lyford and Sobelle distort their bodies as they step through an imaginary wall and seem to enter another dimension. "Amnesia" is a curiosity, all right -- a light but considered tidbit for audiences seeking something completely different.